Conservation Of Native Species Research Articles

Calcium concentrations in the lower Columbia River, USA, are generally sufficient to support invasive bivalve spread

AbstractDissolved calcium concentration [Ca2+] is thought to be a major factor limiting the establishment and thus the spread of invasive bivalves such as zebra (Dreissena polymorpha) and quagga (Dreissena bugensis) mussels. We measured [Ca2+] in 168 water samples collected along ~100 river‐km of the lower Columbia River, USA, between June 2018 and March 2020. We found [Ca2+] to range from 13 to 18 mg L−1 during summer/fall and 5 to 22 mg L−1 during the winter/spring. Previous research indicates that [Ca2+] < 12 mg L−1 are likely to limit the establishment and spread of invasive bivalves. Thus, our results indicate that there is sufficient Ca2+ in most locations in the lower Columbia River to support the establishment of invasive dreissenid mussels, which could join the already widespread and abundant Asian clam (Corbicula fluminea) as the newest invader to an already heavily invaded Columbia River ecosystem. These new data provide important measurements from a heretofore undersampled region of the Columbia River and have important implications for the spread of invasive bivalves and, by extension, the conservation and management of native species and ecosystems.

Cascading effects: insights from the U.S. Long Term Ecological Research Network

AbstractEcosystems across the United States are changing in complex and unpredictable ways and analysis of these changes requires coordinated, long‐term research. This paper is a product of a synthesis effort of the U.S. National Science Foundation funded Long‐Term Ecological Research (LTER) network addressing the LTER core research area of “populations and communities.” This analysis revealed that each LTER site had at least one compelling “story” about what their site would look like in 50–100 yr. As the stories were prepared, themes emerged, and the stories were group into papers along five themes: state change, connectivity, resilience, time lags, and cascading effects. This paper addresses the cascading effects theme and includes stories from the Bonanza Creek (boreal), Kellogg Biological Station (agricultural and freshwater), Palmer (Antarctica), and Harvard Forest (temperate forest) LTER sites. We define cascading effects very broadly to include a wide array of unforeseen chains of events that result from a variety of actions or changes in a system. While climate change is having important direct effects on boreal forests, indirect effects mediated by fire activity—severity, size, and return interval—have large cascading effects over the long term. In northeastern temperate forests, legacies of human management and disturbance affect the composition of current forests, which creates a cascade of effects that interact with the climate‐facilitated invasion of an exotic pest. In Antarctica, declining sea ice creates a cascade of effects including declines in Adèlie and increases in Gentoo penguins, changes in phytoplankton, and consequent changes in zooplankton populations. An invasion of an exotic species of lady beetle is likely to have important future effects on pest control and conservation of native species in agricultural landscapes. New studies of zebra mussels, a well‐studied invader, have established links between climate, the heat tolerance of the mussels, and harmful algal blooms. Collectively, these stories highlight the need for long‐term studies to sort out the complexities of different types of ecological cascades. The diversity of sites within the LTER network facilitates the emergence of overarching concepts about trophic interactions as an important driver of ecosystem structure, function, services, and futures.

Predictive mapping to identify refuges for plant communities threatened by earthworm invasion

Abstract Biological invasions by cryptic ecosystem engineers can alter the ecological and socio‐economic values of ecosystems in ways that may take decades to detect. The invasion of North American glacial refuges by non‐native earthworms offers a prominent but understudied example of a cryptic invasion. Non‐native earthworms are known to alter carbon sequestration, disrupt mycorrhizal networks and homogenize plant communities, but natural resource managers still lack robust protocols to identify and safeguard high conservation value communities (HCVCs) from such invasions. In the absence of such protocols, or reliable methods to eradicate non‐native earthworm populations once established, there is an urgent need for methods to identify HCVCs at risk of or potentially shielded from earthworm invasion by the existence of abiotic barriers to their dispersal or persistence in such sites. We developed species distribution models (SDMs) using in situ field surveys and remotely sensed data to (1) identify factors limiting the occurrence of non‐native Lumbricus earthworms in imperilled coastal Douglas‐fir (Pseudotsuga menziesii) forest and Garry oak (Quercus garryana) and maritime meadow ecosystems endemic to glacial refugia of the Pacific Northwest of North America and to (2) evaluate their influence on plant species diversity and identify abiotic factors capable of preventing their dispersal or persistence at a site. As predicted, shallow, drier soils and steeper terrain limited earthworm occurrence and abundance in our highly heterogeneous study area, and earthworm presence appeared to reduce plant species richness. Our results indicated that HCVCs endemic to shallow‐soil (< 12 ± 3 cm) sites that experience regular summer drought appear to act as refuges from invasion by non‐native earthworms. Our results also elevate concerns for the conservation of deep‐soil habitats not isolated from earthworm invasions by shallow soil, saltwater or other barriers to earthworm dispersal. The SDMs developed here offer guidance to the identification of potential refuges for the conservation of imperilled native species and communities from the detrimental effects non‐native earthworms in glacial refugia of western North America and should thereby facilitate proactive planning by conservation practitioners.

The effects of a zoo environment on free‐living, native small mammal species

One of the main threats to native species conservation is urbanisation. It is causing changes to natural habitats and species composition. Urban green spaces have shown to have conservation value for native species by providing safe spaces in urban areas. They typically contain a variety of habitats and plant species which is correlated with greater abundance and diversity of small mammal species. Zoos are a vital resource for animal conservation and, in some instances, could be considered as an urban green space for native species conservation. Their unique environment provides free-living, native species an abundance of resources including food and shelter. This project involved the live trapping of free-living small mammal species (<40 g) between enclosures in Dudley Zoological Gardens to study the effects of the zoo environment. There were no significant differences found between the total number of captures and trap proximity to enclosures. There was a significant difference in total captures found between different enclosure trapping areas. Generalized linear mixed models were fitted to the data and there were significant relationships between abundance and both habitat type and enclosure species. Habitats associated with semi-natural woodland had the greatest diversity and total captures of small mammals. Total captures were lower in trapping areas that were associated with predatory species. Similar to research on green spaces, habitat was an important factor determining abundance, but predator enclosures were a factor unique to zoos. This study illustrates the potential of zoos as an urban green space and for the study of small mammals.

Non‐native freshwater fish species in the Yellow River Basin: origin, distribution and potential risk

Invasions of non-native fishes are recognized as a serious threat to freshwater biodiversity across the globe. Being the China’s second-largest river, the Yellow River has experienced severe invasion pressure of non-native fishes during recent decades. However, much less is known about species composition and distribution of non-native fishes in this river basin. Here, we investigated and summarized the literatures about non-native freshwater fish in the Yellow River Basin (YRB), to examine their taxonomic diversity, geographical origin, longitudinal distribution and potential risk. We found that 40 non-native fish species, belonging to 9 orders, 18 families and 35 genera, have invaded the YRB. Of which 19 exotic species came from other regions, while 21 translocated species were introduced into the upstream from midstream and downstream of the YRB. The aquaculture was the main vectors responsible for non-native fish introductions. An average of 8.24 non-native fish species was introduced and established per sub-region, accounting for 25.5 % of total fish species. The percentage of non-native species showed a significant unimodal model against average elevation, with the highest values (ca. 70 %) in upstream mainstream reaches and tributaries. Non-native species from historically absent or species-poor orders (Salmoniformes, Osmeriformes and Perciformes) were the most successful invaders. Furthermore, the species composition of non-native fishes changed markedly along the longitudinal gradient (i.e., from source region to downstream). The negative impacts of non-native fish introductions to native fish species, e.g., competition for resource, predation and hybridization were emerged in many introduce regions and could get worse in the future due to global warming and human activities. This study can help improve the management of non-native fish introductions and biodiversity conservation of native and endemic fish species in the YRB.

Evaluation of management factors affecting the relative success of a brook trout eradication program using YY male fish and electrofishing suppression

Removal of non-native fish populations can be crucial to the conservation of native species, but often presents a complex challenge for managers. The goal of Trojan Y chromosome (TYC) programs is to skew the non-native sex ratio until only males remain, leading to eradication. We present results from a simulation model used to explore effects of alternative management approaches on an in-progress mechanical removal and TYC program to eradicate non-native brook trout (Salvelinus fontinalis). Simulation results indicated that stocking fingerling YY males (∼137 mm) was more effective than stocking catchable-sized YY males (∼230 mm), although questions about intercohort competition warrant further investigation. Increasing the proportion of mature fingerling YY males reduced treatment time by increasing the number of YY male spawners and increasing density-dependent mortality on young, mature wild brook trout. Maximizing the spatial distribution of YY male releases may be crucial to program success but is also dependent upon immediate dispersal movements. Principles derived from our results can be broadly applied to the management of other aquatic invaded systems using TYC programs to eradicate non-native species.

Invasive Plants Are a Valuable Alternate Protein Source and Can Contribute to Meeting Climate Change Targets

Agriculture has come under pressure to meet global food demands, whilst having to meet economic and ecological targets. This has opened newer avenues for investigation in unconventional protein sources. Current agricultural practises manage marginal lands mostly through animal husbandry, which; although effective in land utilisation for food production, largely contributes to global green-house gas (GHG) emissions. Assessing the revalorisation potential of invasive plant species growing on these lands may help encourage their utilisation as an alternate protein source and partially shift the burden from livestock production; the current dominant source of dietary protein, and offer alternate means of income from such lands. Six globally recognised invasive plant species found extensively on marginal lands; Gorse (Ulex europaeus), Vetch (Vicia sativa), Broom (Cytisus scoparius), Fireweed (Chamaenerion angustifolium), Bracken (Pteridium aquilinum), and Buddleia (Buddleja davidii) were collected and characterised to assess their potential as alternate protein sources. Amino acid profiling revealed appreciable levels of essential amino acids totalling 33.05 ± 0.04 41.43 ± 0.05, 33.05 ± 0.11, 32.63 ± 0.04, 48.71 ± 0.02 and 21.48 ± 0.05 mg/g dry plant mass for Gorse, Vetch, Broom Fireweed, Bracken, and Buddleia, respectively. The availability of essential amino acids was limited by protein solubility, and Gorse was found to have the highest soluble protein content. It was also high in bioactive phenolic compounds including cinnamic- phenyl-, pyruvic-, and benzoic acid derivatives. Databases generated using satellite imagery were used to locate the spread of invasive plants. Total biomass was estimated to be roughly 52 Tg with a protein content of 5.2 Tg with a total essential amino acid content of 1.25 Tg (~24%). Globally, Fabaceae was the second most abundant family of invasive plants. Much of the spread was found within marginal lands and shrublands. Analysis of intrinsic agricultural factors revealed economic status as the emergent factor, driven predominantly by land use allocation, with shrublands playing a pivotal role in the model. Diverting resources from invasive plant removal through herbicides and burning to leaf protein extraction may contribute toward sustainable protein, effective land use, and achieving emission targets, while simultaneously maintaining conservation of native plant species.

An invasive grass species has both local and broad‐scale impacts on diversity: Potential mechanisms and implications

AbstractQuestionsThe impact of invasive plant species on native diversity varies with spatial scale, with some invaders leading to broad‐scale diversity declines and others to only local declines. These discrepancies may reflect the invaders” capacity to reduce niche opportunities across spatial scales which can be associated with their functional traits. We investigated impact‐scale relationships and trait‐based mechanisms, in areas invaded by the exotic perennial grass species, Bothriochloa pertusa. We examine root traits specifically, as below‐ground competition was considered particularly important to the success of this species.LocationGrassy “ironbark” woodlands of eastern Queensland, Australia.MethodsWe examined plots with varying degrees of invasion by B. pertusa, at multiple spatial scales (up to 1,000 m2) and analysed changes to the species–area relationships (SARs) with increasing invader cover. Changes to SARs were assessed in relation to the invaders” effect on rare (low patch occupancy) and common species in the community. In a separate analysis within the same habitat, we collected root cores across a gradient of invader cover and analysed changes to community root traits that were considered important correlates of competition for space and nutrients.ResultsInvasion‐induced reductions in diversity were pervasive at all scales investigated, and this was associated with a proportionally greater effect on rare species in the community. In the separate root analysis, changes in community root traits with increasing invader cover were potentially indicative of more intense competition for resources rather than space.ConclusionsThe observed regional‐scale dominance of B. pertusa and associated declines in diversity warrant serious concern for the conservation of native plant communities and species in a region already at risk from other anthropogenic threats. Intense competition for below‐ground resources is likely a contributing mechanism to the success of B. pertusa in this study system. Experimental examination of this and other mechanisms would help to validate these findings.

Diversidad y enriquecimiento florístico con especies nativas de bosque mesófilo de montaña, en un bosque urbano de Chiapas, México

Los bosques mesófilos de montaña (BMM) se presentan entre 0.5% y 1% del territorio mexicano y están seriamente amenazados debido a la alta tasa de deforestación. Para contribuir a la conservación de especies arbóreas de BMM, se realizó el presente estudio con los objetivos de (1) determinar la diversidad de árboles en el bosque urbano El Cerrito de San Cristóbal, Chiapas, México, (2) enriquecer florísticamente el bosque urbano El Cerrito de San Cristóbal con la plantación de especies nativas del BMM de Chiapas y (3) describir la diversidad genética introducida mediante el enriquecimiento florístico. A través de un muestreo en parcelas circulares de 1000 m2, se registró la estructura y composición de la comunidad de árboles y, por recorridos, se registraron las especies de herbáceas. Se plantaron 14 especies nativas del BMM para enriquecimiento de El Cerrito y, mediante la técnica PCR-RFLPs de ADN de cloroplasto (tRNL), se determinó la diversidad genética introducida. Se detectó una composición de árboles dominada por especies introducidas hace 40 años (Cupressus lusitánica, Eucalyptus camaldulensis y Pinus pseudostrobus). No se observó reclutamiento de plántulas y juveniles de árboles del dosel y se identificaron algunos individuos de especies nativas establecidos naturalmente. La diversidad genética introducida fue baja por especie, pero en conjunto fue moderada. La baja diversidad por especie se atribuye a que el marcador utilizado es conservador. Los bosques urbanos pueden constituir un sistema de conservación de especies de árboles nativos y de su diversidad genética, al mismo tiempo que se promueve la regeneración y diversificación de bosque urbanos. Este estudio contribuye con la conservación y conocimiento genético de especies arbóreas de bosques de montaña de México.

First report of powdery mildew caused by Podosphaera xanthii on the invasive Verbena brasiliensis in Texas.

Brazilian verbena (Verbena brasiliensis, family Lamiaceae) is a highly invasive plant found throughout the southern portion of the United States. As suggested by its name, it originates in South America but has prospered in the US due to its highly ruderal growing pattern and its ability to tolerate drought and disturbance. During the summer of 2019, sixty-four V. brasiliensis plants were growing in the University of Houston's temperature-controlled greenhouse (Houston, TX). Eight plants exhibited symptoms of powdery mildew infection on the stems and adaxial surface of the leaves. White circular powdery colonies with high numbers of aerially dispersing spores were observed on leaves, seemingly uncorrelated with leaf age. Upon examination, chlorosis of leaf tissue was detected in areas of infection. Conidiophores (n=25) were on average 210 μm in length and produced 6 to 9 conidia in true chains. Base-cells of conidiophores branched from hyphae forming right angles and averaged 35 μm long at the base. Conidia were hyaline, ovate, and measured 28-31 × 19-21μm. These structures are typical of the powdery mildew oidium anamorph of the genus Podosphaera. No chasmothecia were observed within colonies.The morphological characteristics and measurements were consistent with those of Podosphaera xanthii (Braun and Takamatsu 2000). Pathogenicity was confirmed by gently rubbing symptomatic V. brasiliensis leaves onto healthy leaves of V. brasiliensis plants (Lee 2013). Fifteen plants were inoculated, and five remained uninoculated to serve as negative controls. Inoculated plants developed powdery mildew symptoms between 6 to 12 days (averaging 10 days), whereas all controls remained disease-free. DNA was extracted from fungal tissue from the original plant, inocula sample, and the newly infected leaves. The internal transcribed region was amplified using the ITS1f and ITS4 primers (White 1990). Three samples, one from the original plant, the inocula, and the reisolated fungi were sequenced, identified using NCBI BLAST, and the resulting sequences were deposited in GenBank (MN818562, (inocula), MN818563 (re-isolate), MN818564 (original)). All three sequences had 98.7% similarity to the P. xanthii on Brazilian verbena reported in South Korea assession number KJ472787 (Cho et al 2014). All three samples were amplified using the mating type primer sets and PCR protocal described in Brewer et al 2011. All three samples were determined to be MAT1-1-1 based on positive and negative control used for MAT1-1-1 and MAT-1-2-1 Positive controls included DNA from confirmed isolates from MAT1-1-1 and MAT-1-2-1 and negative controls were sterile water. Podosphaera xanthii, a common powdery mildew species, has been reported on a large range of important agricultural hosts, especially cucurbits (McCreight 2006). This is the first formal report of P. xanthii in Texas as well as the first report on Brazilian verbena in the United States. While we did not explicitly measure the pathogen's effect on host fitness, infection may result in a reduction in the plant's invasiveness. As Texas is a large producer of cucurbits, this pathogen could impact agriculture in the state. Given the invasive nature of V. brasiliensis in areas of high disturbance, such as agricultural fields and restored prairies, this discovery has broad importance for both agriculture and the ecological conservation of native species. Acknowledgments This work was supported by the National Science Foundation (Award #DEB-1754287), Texas Ecolab, and the University of Houston. References Braun, U., Takamatsu, S. 2000. Phylogeny of Erysiphe, Microsphaera, Uncinula (Erysipheae) and Cystotheca, Podosphaera, Sphaerotheca (Cystotheceae) inferred from rDNA ITS sequences-some taxonomic consequences. Schlechtendalia 4:1-33. Brewer, M. T., Cadle-Davidson, L., Cortesi, P., Spanu, P. D., and Milgroom, M. G. 2011. Identification and structure of the mating-type locus and development of PCR-based markers for mating type in powdery mildew fungi. Fungal Genet. Biol. 48:704-713. Cho, S. E., Park, J. H., Hong, S. H., Kim, B. S., & Shin, H. D. 2014. First report of powdery mildew caused by Podosphaera xanthii on Verbena brasiliensis in Korea. Plant Dis. 98:8, 1159. Lee, H. B. 2013. First report of powdery mildew caused by Podosphaera xanthii (syn. P. fusca)n cocklebur in Korea. Plant Dis. 97(6), 842. McCreight, J. D. 2006. Melon-powdery mildew interactions reveal variation in melon cultigens and Podosphaera xanthii races 1 and 2. Journal of the American Society for Horticultural Science, 131(1), 59-65.

Arthropod diversity in two Historic Gardens in the Azores, Portugal.

The aim of our study was to characterise and compare the richness and composition of endemic, native (non-endemic) and introduced arthropod assemblages of two Azorean Historic Gardens with contrasting plant species composition. We hypothesised that Faial Botanic Garden would hold higher arthropod diversity and abundance of native and endemic arthropod species due to its larger native plant community. Species were collected using several arthropod standardised techniques between April 2017 and June 2018. We used the alpha diversity metrics (Hill series) and the partitioning of total beta diversity (βtotal) into its replacement (βrepl) and richness (βrich) components, to analyse the adult and total arthropod community. The orders Araneae, Coleoptera and Hemiptera were also studied separately. Our results show that the number of exotic arthropod species exceeds the number of native and/or the endemic species in both gardens, but the arthropod community of Faial Botanic Garden exhibited a higher density of endemic and native species. Despite some minor exceptions, the geographic origins of plant communities largely influenced the arthropod species sampled in each garden. This study improves our knowledge about urban arthropod diversity in the Azores and shows how well-designed urban garden management and planning contribute to the conservation of native and endemic Azorean species.

Diversity of Tree Species in Gap Regeneration under Tropical Moist Semi-Deciduous Forest: An Example from Bia Tano Forest Reserve

In a quest to improve the diversity and conservation of native tree species in tropical African forests, gap regeneration remains all-important nature-promoting silviculture practice and ecosystem-based strategy for attaining these ecological goals. Nine gaps of varying sizes (286–2005 m2) were randomly selected: three each from undisturbed, slightly disturbed and disturbed areas within Bia Tano Forest Reserve of Ghana. Within individual gaps, four transects (North–South–East–West directions) followed by 10 subsampling regions of 1 m2 at 2 m apart were established along each transect. Data showed 63 tree species from 21 families in the study. Although, all estimated diversity indices showed significant biodiversity improvements in all gaps at p &lt; 0.05 level. Yet, there were no significant variations amongst gaps. Additionally, tree species differed between gaps at the undisturbed and the two disturbance-graded areas while no differences were presented between disturbance-graded areas. Balanced conservation between Green Star and Reddish Star species and imbalanced conservation between Least Concern, Near Threatened and Vulnerable species in the International Union for Conservation of Nature (IUCN) Red List were found, showing the reserve’s long-term prospects for economic and ecological benefits of forest management. Thus, there is a need for higher priority for intensive management to regulate various anthropogenic disturbances so as to protect the biological legacies of the reserve.

Knowledge status of predators of the freshwater prawn Cryphiops caementarius (Decapoda: Palaemonidae) in river systems along the North Western Andean region from Perú and Chile

Introduction: Cryphiops caementarius, is an endemic prawn from river ecosystems in Southern Perú and Northern Chile. In these watersheds, natural populations are threatened by multiple anthropic interventions such as mining activities and fishing pressure, but also, by increasing impacts of invasive exotic predators. Information related with predation on C. caementarius is scarce representing a major knowledge gap to ensure suitable management and conservation practices. Accordingly, the further deepening in relevant aspects such as the estimation of populations losses due to predators has been indicated as critical by relevant agencies as FAO. Objective: To conduct a complete registry and classification of C. caementarius predators, updating the knowledge for the Andean region. Methods: A thorough bibliographic review on existing information on C. caementarius' predators from Perú and Chile was carried out calculating percentage of occurrence, relative frequency of species, zoogeographic origin, trophic structure, phenotypic attributes, river zone that inhabits and life stage of incidence. The registry was complemented using semi-structured interviews from prawn´s fishers in central-Northern Chile. Results: C. caementarius is predated along the entire fluvial network (estuary, potamon and rhithron) by 21 species of opportunists, carnivores, omnivores and herbivores, mostly aquatic vertebrates. In turn, these belong to 15 families and six guilds of native, exotic and cosmopolitan species. Approximately 86 % predate on adult prawns, whilst, 71 % on juveniles and 24 % on larvae. More than 40 % of the predation pressure seems to be exerted by native waterfowls and 24 % by exotic fish. Conclusions: The results emphasize the relevance for conservation of native species of predators in the Andean region and the need of control measures on exotic species in a latitudinal basis. Accordingly, this review may serve as an initial decision-making tool for future conservation efforts both on prawns and native biota, but also supporting restocking actions, fisheries management plans and risk assessment for C. caementariuspopulations across the Andean region.

Forest resources: conservation, management and sustainable development in Khandesh Region of Maharashtra (India)

Forest is the second largest land use in India next to agriculture. Forests are regarded 'economic-engines' and 'nature's water factories'. Most importantly, they help make possible our breathing. Despite their immense value, they are being denuded at alarming rate. The rate of deforestation vis-à-vis exploitation and afforestation have become a matter of grave concern in recent times. The present study informs traditional uses for food, fuel, fodder, house and hut constructions, medicinal utilities, besides plant diversity in Dhule, Nandurbarand Jalgaon districts, comprising a northern part of the state of Maharashtra (India). Traditional plant-based practices and their in-depth knowledge are an integral part of forest management but may be blended with modern scientific knowledge to benefit all. Impediments in restoration and management of native biodiversity appeared because of over-dependency on forests, lack of alternatives and technical and scientific knowledge of the local tribal people. The local alternatives in the form of cottage industries like broommaking, bidi-wrapping, artefacts, traditional fixtures, tribal handicrafts and even the tribal paintings, etc. have to be filliped. Fuel-dependency, one of the major reason for deforestation, may be minimized by providing gas stoves, kerosene stoves and the likes by Government at free of costs or at the most low costs. Captive plantation is a dire necessity to meet needs of tribals in respect of timber and even fodder. Some attempts by the Government Forest Departments and NGO's selecting some plant species have also proved unfit in the region. Multipurpose tree species be planted on waste lands along roads, railways lines, govt.-owned lands, barren lands, river banks, along canals, besides in places of denuded forest areas. Timing and seasons of collections of plants, their parts or products for food, medicine and other miscellaneous purposes should be suggested with proper methods and techniques. The knowledge of conservation of native plant species of the indigenous tribal communities should be brought into a clearer focus and these should be implemented if found suitable. This will help favor conservational strategy in the region. Apart from these, exotic sources of income e.g. candle making, weaving, tailoring, etc. will boost their economy and simultaneously help reduce their dependency on the local forests.

Environmental factors affecting the distributions of the native Eurasian beaver and the invasive North American beaver in Finland

When planning conservation and reintroductions of native species and control of invasive species, it is important to understand the environmental factors affecting species distributions. Habitat suitability largely determines where species can occur, but in addition to habitat and food resources, it is important to also consider human disturbance and climate when mapping possible distributions. We studied the environmental factors affecting the present distribution of the native Eurasian beaver (Castor fiber) and the invasive North American beaver (C. canadensis) in Finland. We compared the role of food resources, aquatic habitat type, anthropogenic disturbance and climate for beaver occurrence with species distribution models. We created maps of suitable areas for the two species and compared how the results would change if these two ecologically similar species were modelled together. We found that aquatic habitat type and climate largely explain the present distributions of the species. In addition, there were differences between the species in their preference for food resources, aspen, birch and grey alder. However, we suspect that the species' reintroduction history, i.e. the differences in the present environment, much explain the differences found between the species. We conclude that when planning possible reintroductions for the Eurasian beaver, factors other than food resources should also be considered. We also suggest that studies on habitat suitability should consider the history of the species and include data from different environments. Thus, more comprehensive information for management planning would be achieved and a better ability to predict the location of optimal areas for the species.

Forty-four years of global trade in CITES-listed snakes: Trends and implications for conservation and public health

Trade in venomous and non-venomous snakes can negatively impact wild snake populations and may drive snakebite risk for people. However, we often lack sufficient trade data to identify where the potential risks for snake population decline and snakebite are highest. Currently, the legal, international trade of 164 snake species is regulated by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). We analyzed CITES-listed snake trade from 1975 to 2018 using the recently released shipment-level CITES Trade Database to identify spatiotemporal trends of snake trade and generate insights regarding snake conservation and potential public health risks from snakebite. Commercially purposed pythons dominated the global snake trade, comprising 38.8% of all traded snakes. Live snakes were mainly exported by Ghana, Indonesia, Togo, and Benin, and imported by China and the USA. Venomous snake trade comprised 10.8% of all traded snakes, and over 75% of wild-sourced venomous snakes came from Indonesia. Although traded snakes in recent years are increasingly comprised of captive-bred animals, the majority of snakes are still wild-sourced (> 60% between 2015 and 2017), including IUCN-listed species, with potentially detrimental impacts on conservation status. Further, the CITES Trade Database reveals geographic regions where venomous snakes are sourced from the wild, posing potential risks to snake catchers, traders, and pet owners. The database also documents the movement of non-native snake species through trade, with implications for conservation of native species. This study represents the first global analysis focused specifically on CITES-listed snake trade using the CITES Trade Database.

Stingless Bees (Melipona subnitida) Overcome Severe Drought Events in the Brazilian Tropical Dry Forest by Opting for High-Profit Food Sources.

In the Brazilian Tropical Dry Forest, the Caatinga, stingless bees (Apidae, Meliponini) need to adjust their foraging behavior to a very short and unpredictable blooming period. Melipona subnitida Ducke 1910 is one of the few meliponine species adapted to the environmental peculiarities of this biome. To get an insight into how these highly eusocial bees are able to maintain their perennial colonies despite extended periods of food scarcity, we asked the following questions: (1) At which plant species do colonies of M. subnitida collect their food during the rainy season? And (2) are there any plant species during the dry season, from which the colonies may profit for replenishing their food stores? During 1year, we collected monthly honey and pollen samples from recently built storage pots of five colonies of M. subnitida and identified the botanical origin of the collected resources. In the course of our study, the colonies foraged at native trees, shrubs, and herbaceous species, demonstrating the importance of all plant strata for the bees' diet. Profitable plants, which bloom mainly during the rainy season and usually produce a great number of flowers, were frequently sampled in new pots throughout the entire study, even during the dry season. From our results, we compiled a list of the most important plant species providing floral resources for bees throughout the year, including periods of drought. We recommend these plants for restoration areas to improve the conservation of native bee species and local beekeeping in the Brazilian Tropical Dry Forest.

Land‐use intensification promotes non‐native species in a tropical island bird assemblage

AbstractHabitat loss and non‐native species are two key drivers of biodiversity decline. The importance of their interactions is widely recognized, but remains poorly understood. We used the endemic‐rich bird assemblage of São Tomé Island to study this type of interactions. We built species‐specific binomial generalized linear models for 33 terrestrial bird species, based on presence–absence data from 2398 sampling points. Meta‐analysis techniques revealed that land use was more important in explaining distribution than topographic variables, rainfall, or distance to coast for the studied bird species. Native species were more likely to occur in remote rainy forests at higher altitudes, whereas non‐native species were more likely to occur in non‐forested ecosystems, being associated with humanized lowland areas in the drier flat regions of São Tomé. The susceptibility of anthropogenic ecosystems to the establishment of non‐native birds suggests that disturbance favours these species. An analysis of species feeding guilds further suggests that these habitat associations might be linked to resource availability, as a large proportion of non‐native species rely on seeds, which are clearly more available outside the best‐preserved forests. Contrarily, very few native birds seem to be using this resource, and instead rely on more complex ecological interaction, such as carnivory and frugivory. This difference may reduce the chance of negative interactions between native and non‐native species (e.g. competition), but this should not be misunderstood for a lack of negative effects of the latter. Our results indicate that land‐use intensification is the key driver of biodiversity changes on São Tomé, potentially facilitating the expansion of non‐native species and demoting ecological complexity. Therefore, protecting the best‐preserved forests is the single most important measure to ensure the conservation of native species.

Characterization and Justification of Trees on an Inner-City Golf Course in Halifax, Canada: An Investigation into the Ecological Integrity of Institutional Greenspace

Institutional greenspaces such as golf courses, cemeteries, military bases, hospitals, and university campuses are not generally revered for their ecological integrity. The existence of golf courses in particular has been heavily debated due to widespread perceptions of these spaces as environmentally degrading. Though much of the total area of golf courses is occupied by heavily manicured lawns, Canadian golf courses tend to be well treed and thus show significant potential to enhance forest coverage and contribute to the conservation of native tree species when established on previously unforested land. To explore this potential, a tree inventory was carried out on an inner-city golf course in Halifax, Nova Scotia, and findings compared to an earlier inventory of more naturalized (i.e., ingrowth) forest areas in the same city. Based in the Acadian Forest Region, this case study used the characteristics of a healthy and mature Acadian Forest as a model for ecological integrity. It was found that both the golf course and the ingrowth populations were largely representative of a mixedwood Acadian forest. Likewise, both populations were in a similar stage of regeneration and exhibited similar stresses. These results suggest that if improved forest management approaches are employed, golf courses will effectively strengthen the ecological integrity of urban forests. This is an especially important finding in the climate change era when tree populations are likely to be subjected to new environmental stressors which may be alleviated via the human intervention that is available on managed lands such as institutional greenspaces.

Can the impacts of cold-water pollution on fish be mitigated by thermal plasticity?

Increasingly, cold-water pollution (CWP) is being recognised as a significant threat to aquatic communities downstream of large, bottom-release dams. Cold water releases typically occur during summer when storage dams release unseasonably cold and anoxic hypolimnetic waters, which can decrease the temperature of downstream waters by up to 16°C. Depending on the release duration, these hypothermic conditions can persist for many months. The capacity of ectothermic species to tolerate or rapidly adjust to acute temperature changes may determine the nature and magnitude of the impact of CWP on affected species. This study assessed the impacts of an acute reduction in water temperature on the physiological function and locomotor performance of juvenile silver perch (Bidyanus bidyanus) and examined their capacity to thermally compensate for the depressive effects of low temperatures via phenotypic plasticity. Locomotor performance (Ucrit and Usprint) and energetic costs (routine and maximum metabolic rate) were measured at multiple points over a 10-week period following an abrupt 10°C drop in water temperature. We also measured the thermal sensitivity of metabolic enzymes from muscle samples taken from fish following the exposure period. Cold exposure had significant depressive effects on physiological traits, resulting in decreases in performance between 10% and 55%. Although there was partial acclimation of Ucrit (~35% increase in performance) and complete compensation of metabolic rate, this occurred late in the exposure period, meaning silver perch were unable to rapidly compensate for the depressive effects of thermal pollution. The results of this study have substantial implications for the management of cold water releases from large-scale dams and the conservation of native freshwater fish species, as this form of thermal pollution can act as a barrier to fish movement, cause reduced recruitment, ecological community shifts and disruptions to timing and success of reproduction.